Lake Poygan vs Rush Lake
Water quality, depth, fish species, and recreation comparison.
Rush Lake has a higher water quality grade (C, Fair) than Lake Poygan (F, Very Poor). Both are in Winnebago County, Wisconsin.
Both Lake Poygan and Rush Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. Rush Lake (C) is materially cleaner than Lake Poygan (F). A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.
For a recreational visitor, the wider grade gap is decisive — Rush Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?
Lake Poygan
Very murky, less than 2.5 ft of visibility.
Rush Lake
Very murky, less than 3.2 ft of visibility.
Side-by-Side Metrics
| Metric | Lake Poygan | Rush Lake |
|---|---|---|
| Overall Grade | F (Very Poor) | C (Fair) |
| Water Clarity | 2.5 ft | 3.2 ft |
| Phosphorus | No data | 26 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 11 ft | 5 ft |
| Surface Area | 14.0K acres | 2.7K acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Rush Lake wins on overall water quality with a Grade C versus Lake Poygan's Grade F. Water clarity: 3.2 ft vs 2.5 ft. For fishing diversity, Rush Lake also leads with 0 species.